The present invention relates to liquid crystal compositions and more particularly to liquid crystal compositions which can be used over a wide range of temperatures.
The usefulness of liquid crystal display devices has attracted attention from many fields and the devices have been intended for a wide variety of applications. As a result, it is necessary to prepare liquid crystals having the properties which satisfy the necessary conditions of application.
For example, a panel display using liquid crystals for cars requires a nematic liquid crystalline temperature range (nematic range) of -40.degree. C. to 100.degree. C. To meet this requirement, a plurality of liquid crystal compounds have been mixed in the past. The properties of these liquid crystal mixtures and the methods of making them are described in the patent literature such as U.S. Pat. Nos. 4,216,109 and 4,290,905. Unfortunately, as is apparent from the above prior patent literature, liquid crystal compositions having a wide nematic range have not yet been obtained. Especially at low temperatures, they are not operable.